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On-line version ISSN 2078-5135Print version ISSN 0256-9574

SAMJ, S. Afr. med. j. vol.99 n.3 Cape Town Mar. 2009

SCIENTIFIC LETTERS

From 'playstation thumb' to 'cellphone thumb': the new epidemic in teenagers

Safura Abdool Karim

To the Editor: Repetitive strain injury (RSI) is a painful condition that can sometimes result in substantial disability. RSI often affects the neck, the back and particularly the arms and hands, as a result of soft-tissue injury from repeated movement.

RSI is found primarily in adults who perform repeated movements such as those involved in typing or playing musical instruments. It is commonly named according to the part of the body affected, e.g. tennis elbow, Rubick's wrist and playstation thumb.

In 2004, I studied1 the effect that playstation games had on the prevalence of RSI in children. In the 2004 study, 37.5% of the pre-teens surveyed played playstation. At that time, it appeared that this condition had the potential to become an epidemic in children, but changes in technology over the last 4 years have resulted in a different course. With increasing age, time spent on playstation decreases rapidly. In teenagers at two high schools in Durban, only 5.6% of the people surveyed regularly play. However, 318 of the 320 teenagers interviewed use mxit or similar communication text message forums on their cellular phones. There has been a substantial increase in the amount of time teenagers spend on their cellular phones sending text messages, thereby potentially affecting the prevalence of RSI in this group.

For this study a total of 320 students in Grades 8 - 11 were interviewed, 80 teenagers in each grade. This included the same population interviewed in the 2004 study, now in high school. This study comprised questions asking how often, if at all, they played playstation, as well as how often they visited chat forums on their cellular phones. I also enquired whether they had any of the primary and secondary symptoms of RSI.

In the survey, students were asked if they experienced pain or tingling in their neck, hands and/or back, symptoms typical of the primary stages of RSI. In addition they were asked if they had blisters on their fingers, a secondary symptom. Of the 320 interviewed, 167 (52.2%) had at least one of the primary symptoms (Table I); of those, 150 (46.9% of the whole group) had both symptoms. In addition 125 (39.1%) of those interviewed reported blisters on their fingers after engaging in the cellular phone messaging.

The thumb is the least dexterous of all our fingers and is not suited to the repetitive movements required to type on a cellular phone keypad. This is why computer keyboards only require the thumb to be used for the spacebar. The rapid increase in the use of cellular phones for communicating with text messages is leading to an increase in RSI in teenagers. 'Cellphone thumb' is somewhat different from 'Blackberry thumb' because it involves multiple thumb presses, usually with one thumb, to obtain most letters of the alphabet on a 12-button keypad. The availability of low-cost text messages through mxit over the last few years has increased 'typing' on 12-button keypads and has created the RSI problem 'cellphone thumb' in teenagers.